On 13/06/2012, at 3:51 PM, Willy Tarreau wrote:
> Hi Roy,
>
> On Tue, Jun 12, 2012 at 10:35:12PM -0700, Roy T. Fielding wrote:
>> On Jun 12, 2012, at 9:34 AM, Tim Bray wrote:
>>
>>> Aaaaaaaand, it turns out MNot was right; I checked with an expert, and 451 is heavily used for ?redirect? in the Msft ecosystem, notably including HotMail?s hundreds of millions of users. Consider it ?4xx? (which I would still argue for as opposed to 5xx). -T
>>
>> 4xx indicates an error by the user or user agent. I don't see
>> any reason (aside from literary) that would justify using a 4xx
>> code for this. 5xx is typically used for non-authoritative
>> responses or server-imposed limitations -- a status that might
>> be different if the user agent chose a different intermediary
>> or tried again later. Hence, 5xx makes more sense here.
>
> I don't completely agree here : for me, 5xx means that the error is not
> the client's fault and that it might randomly work if the client tries
> again, which is why network errors fall into this category, as opposed
> to the 4xx error by the user/user agent as you explained (and which I
> agree with).
This is completely off base.
If the client retries the request, it might indeed work again -- depending on what network path they're using, etc. That's why all of the intermediation-focused errors are in 5xx.
> If a client requests a resource that is forbidden for legal
> reasons, we're typically in the situation where the user caused the error
> to happen by requesting this resource, and where if he tries again he will
> get the same error again. Much like 403 or 404. 5xx would be appropriate
> if the server was not able to verify in a database or referential whether
> the resource is legally permitted or not.
Sorry, what?
--
Mark Nottingham http://www.mnot.net/